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are all commercial m4s overgassed? and what are the signs of m4 being overgassed? all my friends run h or h2 on there m4s...what are the benefits?
Try here. (http://lmgtfy.com/?q=site%3Am4carbine.net+overgassed+AR-15)
kiki
So all your friends have full auto M4's? What unit they in.:rolleyes:
Your freinds are shooting AR15's not M4's! Run a Carbine buffer and spring and you'll be fine.:D
H or H2 buffer. The former is standard in the M4, the latter in the M4A1.
Ok, yes there m4 clones/carbine/semi wanna be...lol......
I'd say unless its race gun, run the heaviest buffer that your gun will reliably cycle. It'll help smooth out that recoil impulse....The A5 is going to be my next expense, heard nothing but good things.
are all commercial m4s overgassed? and what are the signs of m4 being overgassed? all my friends run h or h2 on there m4s...what are the benefits?
My theory is that most of your 'commercial' spec rifles (bm, rra, dpms, ect) are overgassed to handle the cheap 223 spec ammo the owners will probably feeding them vs milspec where the system is designed to run around the 5.56 spec.
Like i say its just my theory.
This might help too http://www.ewp.rpi.edu/hartford/~ernesto/SPR/LeBlanc-FinalReport.pdf
This might help too http://www.ewp.rpi.edu/hartford/~ernesto/SPR/LeBlanc-FinalReport.pdf
That was a very comprehensive article. Not to start a piston vs di war but what suprised me was this:
Also, the offset loading of the bolt carrier causes higher friction loads between
the carrier and the inside of the upper receiver. The larger internal loads can cause
premature wear and failure of components over time. Even in the larger rifle length
external piston gas systems the predicted loads are larger by a factor of ten
Loads that are larger than a factor of ten worry me. So maybe there is some truth to those who say the external piston is harder on components.
polymorpheous
11-12-12, 01:24
Gas port size is the single most important determining factor when figuring out if your gun is over gassed.
If you buy a Colt series carbine (6920, 6933, etc...) you will have a proper sized gas port. If you purchase something from BCM, Daniel Defense, LMT or Noveske (there may be others) you will also have a proper port size.
Some of the other companies make their ports larger so that people who buy their crap can also shoot crappy ammo (Tula, Wolf, Brown Bear and other lower powered ammo) and allow the gun to cycle correctly.
The larger issues arise when you have one of those others and you shoot 5.56 ammo and now you are getting even more gas pressure. Or you add a suppressor and now you get even more gas flowing through the weapon and beating it up even more.
polymorpheous
11-12-12, 03:04
If you buy a Colt series carbine (6920, 6933, etc...) you will have a proper sized gas port. If you purchase something from BCM, Daniel Defense, LMT or Noveske (there may be others) you will also have a proper port size.
Some of the other companies make their ports larger so that people who buy their crap can also shoot crappy ammo (Tula, Wolf, Brown Bear and other lower powered ammo) and allow the gun to cycle correctly.
The larger issues arise when you have one of those others and you shoot 5.56 ammo and now you are getting even more gas pressure. Or you add a suppressor and now you get even more gas flowing through the weapon and beating it up even more.
Dude!
Parts are parts!
are all commercial m4s overgassed? and what are the signs of m4 being overgassed? all my friends run h or h2 on there m4s...what are the benefits?
IMO "overgassed" is a moving target depending on what ammo is being used. If using NATO spec 5.56 pressure ammunition, then the answer is likely yes. If using commercial grade .223 ammunition then the answer is likely no. If you want to shoot both, you'll need to buffer up or down as appropriate or try to find a middle ground (i.e. compromise) that will run both since the platform's gas system is not adjustable (unless you count gas port erosion).
IMO "overgassed" is a moving target depending on what ammo is being used. If using NATO spec 5.56 pressure ammunition, then the answer is likely yes. If using commercial grade .223 ammunition then the answer is likely no. If you want to shoot both, you'll need to buffer up or down as appropriate or try to find a middle ground (i.e. compromise) that will run both since the platform's gas system is not adjustable (unless you count gas port erosion).
That makes no sense. Either a weapon is overgassed or not; REGARDLESS of ammo. Ammo does not dictate whether or not a gun's gasport is sized correctly. Overgassed guns like 223, sure, but that does not mean it's "correct" or true to spec.
To really determine if a gun is overgassed, you need to check that it's cyclic rate falls into the spec of 700-900 rpm with GI ammo.
Just orderd a H2 for my carbine, since i normally shoot both 223/5.56 what ever i come across cheap.....went to wallyworld bought 500 rnds of federal 223...
Went back the next day all was gone.....was suprise to find winchester 5.56 @
Wally world...but @ $11.98 per 20 ill pass.....lol
Ammo does not dictate whether or not a gun's gasport is sized correctly.
You are correct, but ammo does dictate how much gas/energy is transferred to the BCG which is critical to the reliable function of the platform. But markm is hit it on the nose, the cyclic rate determines whether or not a gun is under/overgassed.
Overgassed guns like 223, sure, but that does not mean it's "correct" or true to spec.
In the civilian world where we buy own own fodder we can be true to spec or "correct" and have guns that won't run with supplied ammo or we can select a gas port/buffer "more properly" matched for what we have on hand.
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